The removal behavior of model contaminants from polyethylene terephthalate (PET) film in aqueous detergent solutions was examined using a microscopic image analysis system. Carbon black, iron (III) oxide and oleic acid dyed with Sudan III as model contaminants were deposited onto the PET films. The PET film was cleaned using a frequency-modulated ultrasonic cleaning apparatus monitoring with a sound pressure meter. The detergency was calculated from the total area of the contaminant deposited on the PET film. It was found that the detergency increased with increasing sound pressure and temperature. The soil removal was enhanced by the adding of sodium hydroxide. In the presence of sodium dodecyl sulfate, the removal of the dyed oleic acid increased, whereas that of particulate soils decreased considerably. To compare this with a model detergent system, ultrasonic washing was carried out using artificially soiled PET fabric. The detergency of the soiled fabric was enhanced by increasing sound pressure. The experimental results in this study show that ultrasonic waves can be utilized for textile washing